Infrared radiator modules having multiple infrared radiators arranged in a radiator plane are known, and are often used as panel radiators.
Panel radiators have a front side and a rear side. Often, the front side of the panel radiator faces a process space such that only the radiation emitted towards the front side of the panel radiator is available as useful radiation in this type of radiator module. It is therefore desirable to have the maximum possible portion of the radiation emitted by the infrared radiators directed at the front side of the panel radiator since only this portion can be used for irradiation of a substrate.
As a general rule, infrared radiators emit undirected radiation. In order to provide the maximum possible fraction of the radiation emitted by the infrared radiators for substrate irradiation and simultaneously attain a high irradiation intensity in the process space, the infrared radiators usually have a common reflector allocated to them that extends at a predetermined distance from the infrared radiators.
The reflector reflects the portion of the radiation that reaches the rear side of the panel radiator and deflects the portion of the radiation in the direction of the substrate.
An irradiation apparatus including a radiator module of this type is known, for example, from DE 10 2013 105 959 A1. The radiator module includes a housing, in which multiple twin-tube infrared radiators are arranged. Moreover, the housing is provided with a reflector on its inside such that a maximum possible fraction of the emitted infrared radiation is coupled onto the substrate. Known radiator modules therefore usually include a rear space that is bordered by the infrared radiators on one side and the reflector on the other side.
The use of a separate reflector is disadvantageous though in that the reflector does not always reflect radiation right at the substrate, but rather, reflected radiation is also incident on neighbouring infrared radiators and can be reflected again there. This is usually observed to be associated with radiation losses that can impair the radiation efficiency of the radiator module. This problem is particularly evident if high irradiation intensities are to be attained with the radiator module. Radiator modules that are designed for high irradiation intensities are usually made to have a compact design, in which neighbouring infrared radiators are disposed at a minimum distance from each other. However, the probability of undesired reflection or absorption of radiation on the infrared radiators increases with decreasing distance of the infrared radiators. This impairs the energy efficiency of the radiator module.